Natural clays have many advantages in order to be used in the pharmaceutical industry. However surface modification is needed for the adsorption of low or moderately water-soluble drug molecules on ...clays such as bentonite. Four surfactant loaded clays were prepared, characterized and tested for paracetamol loading in this study. Organoclays were characterized using FTIR, Raman, XRD and SEM-EDX analysis. Characterization studies confirmed the successful intercalation of surfactant molecules into bentonite. Then organoclays were tested for drug loading using paracetamol which is a widely used analgesic drug . Loading tests showed the improved adsorption capacity of bentonite after modification with surfactants. DTAB loaded bentonite showed the highest adsorption capacity for paracetamol and surfactants followed the order as DTAB > DPC > SDS > DBSA to be more effective on the adsorption capacity of bentonite. Paracetamol adsorption on organoclays was due to hydrophobic interaction with the contribution of pi dispersion interactions.
The present study is focused on the characterization of solubilization of poorly soluble drugs, that is, sulfamethoxazole (SMX) and trimethoprim (TMP) by cyclodextrins (α-, β-, and γ-CDs) and anionic ...surfactant sodium dodecyl sulfate (SDS). The phase solubility diagrams drawn from UV spectral measurements are of the AL type and indicate an enhancement of SMX and TMP solubility in the presence of CDs. Complex formation tendency of TMP with CDs followed the order: γ-CD > β-CD > α-C. However, the complex formation constant values, for SMX-CD system yielded the different affinity and follow the order: β-CD > γ-CD > α-CD. With taking into consideration of solubilization capacity of SDS micelles, it has been found that the solubility enhancement of TMP is much higher than that of SMX in the presence of SDS micelles. The binding constants of SMX and TMP obtained from the Benesi-Hildebrand equation are also confirmed by the estimated surface properties of SDS, employing the surface tension measurements. In order to elucidate the solubilization characteristics the surface tension measurements were also performed for nonionic surfactant Triton X-100. Polarity of the microenvironment and probable location of SMX and TMP were also discussed in the presence of various organic solvents.
Religious people live longer than nonreligious people, according to a staple of social science research. Yet, are those longevity benefits an inherent feature of religiosity? To find out, we coded ...gravestone inscriptions and imagery to assess the religiosity and longevity of 6,400 deceased people from religious and nonreligious U.S. counties. We show that in religious cultural contexts, religious people lived 2.2 years longer than did nonreligious people. In nonreligious cultural contexts, however, religiosity conferred no such longevity benefits. Evidently, a longer life is not an inherent feature of religiosity. Instead, religious people only live longer in religious cultural contexts where religiosity is valued. Our study answers a fundamental question on the nature of religiosity and showcases the scientific potential of gravestone analyses.
A method for real-time three-dimensional (3-D) ultrasound imaging using a mechanically scanned linear phased array is proposed. The high frame rate necessary for real-time volumetric imaging is ...achieved using a sparse synthetic aperture beamforming technique utilizing only a few transmit pulses for each image. Grating lobes in the two-way radiation pattern are avoided by adjusting the transmit element spacing and the receive aperture functions to account for the missing transmit elements. The signal loss associated with fewer transmit pulses is minimized by increasing the power delivered to each transmit element and by using multiple transmit elements for each transmit pulse. By mechanically rocking the array, in a way similar to what is done with an annular array, a 3-D set of images can be collected in the time normally required for a single image.
The adsorption of cationic dye toluidine blue (TB) onto fly ash has been studied from aqueous solution, in the presence of cationic surfactant cetyl pyridinium chloride (CPC) and anionic surfactant ...sodium dodecyl sulfate (SDS) at three different temperatures.
Two-step adsorption isotherms are observed for TB adsorption in aqueous solution. Isotherm shape is also preserved in the presence of CPC. The equilibrium saturation adsorption capacities of fly ash for TB decreased in the presence of CPC as a result of the competitive adsorption for the same sites between the same charged dye and surfactant molecules. Four-region adsorption isotherms are obtained in the presence of SDS. The adsorption of the cationic dye at low SDS concentration is enhanced by adsolubilization phenomenon because of the favorable interaction with the negatively charged adsorbed micelles. Above the critical micelle concentration free micelles are formed, TB is distributed between the free and the adsorbed aggregates, and therefore the global adsolubilization decreases. The order of changing of Freundlich isotherm constant (n) gives information about isotherm shape whether two-step or four-region adsorption isotherm. Adsorption isotherms of SDS and CPC in aqueous solution have also been constructed for interpreting adsorption results of TB in the presence of surfactants.
A measurement of vector analyzing powers in elastic deuteron-carbon scattering has been performed at the Cooler Synchrotron COSY of Forschungszentrum Jülich, Germany. Seven kinetic beam energies ...between 170 and 380 MeV have been used. A vector-polarized beam from a polarized deuteron source was injected, accelerated to the final desired energy and stored in COSY. A thin needle-shaped diamond strip was used as a carbon target, onto which the beam was slowly steered. Elastically scattered deuterons were identified in the forward direction using various layers of scintillators and straw tubes. Where data exist in the literature (at 200 and 270 MeV), excellent agreement of the angular shape was found. The beam polarization of the presented data was deduced by fitting the absolute scale of the analyzing power to these references. Our results extend the world data set and are necessary for polarimetry of future electric dipole moment searches at storage rings. They will as well serve as an input for theoretical description of polarized hadron-hadron scattering.
Optics matching schemes for linac-based light source Liu, C.; Talman, R.; Krafft, G.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2014, Letnik:
735
Journal Article
Recenzirano
Despite its small average beam current limit, a linac has features that make it attractive as an X-ray source: high energy, ultra-low emittance and energy spread, and flexible beamline optics. Unlike ...a storage ring, in which an undulator radiation source necessarily is short and positioned at the electron beam waist, in a linac the undulator can be long and the electron beam can be adjustable to have a virtual waist far downstream towards the X-ray target to produce a convergent X-ray beam. Using a planned CEBAF beamline as an example, we show here that we can overcome a factor of 2000 in the beam current to produce a monochromatic hard X-ray source comparable with, or even exceeding, the performance of an X-ray line at a third-generation storage ring. Even with no monochromator, the X-ray energy bandwidth can be as small as 0.1%. We discuss the optimal conditions which produce maximum X-ray flux density by focusing the electron beam for twocases: one is based on the waist-at-target (WAT) scheme, while the other goes beyond the WAT scheme. Both cases were verified by simulations using the SRW code.
The traditional linear envelope model is widely used in linac design and on-line tuning. However, for the simultaneous acceleration of multicharge states, the associated transfer matrix acts ...differently on each species with different charge to mass ratios and the traditional linear envelope model cannot be utilized. A direct way to handle multicharge state acceleration is by using multiparticle tracking, which can be high in model detail, but is typically lacking in computational efficiency to the extent where it is not suitable for on-line beam tuning of a linac. In this paper, a new approach of adapting a conventional linear envelope model to multicharge state acceleration is developed. The lattice of the proposed Facility for Rare Isotope Beams (FRIB) is used to test this technique in both the linac and the bend/folding segments of the machine. Results are benchmarked with the multiparticle tracking code IMPACT to both verify the accuracy of the model and clarify improvements in computational efficiency.
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